Television deflection and power supply circuits



l. G. MALOFF 2,896,114 'TELEVISION DEPLECTION AND POWER SUPPLY CIRCUITSJuly 21, 1959 Filed April 18, 1957 I N V EN TOR. [barry 1142?]015 BY l I7- l ATTORNEY United States Patent 'v TELEVISION DEFLECTION AND PWlERSUPPLY CIRCUITS Ioury G. MaloH, Pennsauken, NJ., assignor to RadioCorporation 'of America, a corporation of Delaware This inventionrelates to horizontal deflection and high voltage power supply circuitsfor television receivers and the like and in particular to such circuitsutilizing transistors as active amplifying elements.

Transistors are normally relatively low power devices, especially whencompared with vacuum tubes'. Accordingly,lt has generally beenconsidered necessary to use separate transistors l) for generating therequired deflection current for the horizontal deflection winding of animage reproducing device such as a kinescope and, (2) for developing thelrequired ultor voltage for the kinescope. Whenattempting to utilize asingle output transistor for generating the required deflection currentand for developing the required high ultor voltage a condition known asringing has been observed in the high voltage supply which interferswith the deflection circuit. This condition produces undesired effectson the kinescope raster. It would be desirable to generate the requireddeflection current and develop the required high voltage with onetransistor, while preventing ringing in the deflection circuit. Inaddition to the foregoing objectives, the deflection .and high voltagecircuits should 'be arranged, if possible, so that the heat generatedduring the operation of the circuit, may be transferred as expeditiouslyas possible, particularly sincetransistors are temperature sensitive andtheir operating characteristics vary at elevated operating temperatures.

It. is, accordingly, an object of the present invention to provideimproved horizontal deflection and high voltage power supply circuitsfor television receivers and the like.

It is another object of the present invention to provide improvedhorizontal deflection and high voltage power supply circuits fortelevision receivers and the like wherein a single transistor may beused to provide the required deflection current and high ultor voltagefor the television kinescope.

It is yet another object of the present invention to provide an improvedhorizontal deflection circuit for television receiving systems and thelike wherein maximum transfer of generated heat is provided and ringingin the deflection circuit is minimized.

vIt is still another object of the present invention to provide improvedhorizontal deflection and high voltage power supply circuits fortelevision receivers and the like wherein the high voltage is isolatedfrom the deflection circuit during the scan or trace portion of thedeflection cycle, thereby preventing ringing in the deflection circuit.

-A transistor horizontal output circuit includes, in accordance with onefeature of the invention, a single transistor which is operated as acommon emittergrounded collector amplifier. Thus, high gain circuitoperation is provided and the transistor may be mounted in directthermal contact with the television chassis for optimum heat transfer.

High voltages for the television image reproducing device or kinescopeare derived by rectifying llyback pulses as the output transistor isturned off in response 27,896,114 Patented July 2l, 1959'Y to pulsesfrom the horizontal oscillator. `In accordance With another feature ofthe invention, interaction of the high Voltage supply circuit with thedeflection circuit andthus ringing of the deilection circuit areprevented by connecting a unilateral conducting device in series betweenthe primary of the deflection transformer and the primary of the highvoltage transformer so that the unilateral conducting device conductsduringrflvback and isolates the high voltage supply circuit from thedeflection circuit during the trace or scan portion of the deflectioncycle.

The novel features that are considered characteristic of thisy inventionare set forth with particularity4 in the appended claims. The inventionitself, however, both as to its organization and method of operation,-aswell as additional objects and advantages thereof, will 'best beunderstood from the following description when reati` in connection withthe accompanying drawing. In the drawing, the single figure isaschematic circuit diagram, partially in block kdiagram form, of atelevision receiver which includes horizontal and high voltage powersuppltr circuits embodying the present invention.

-Refern'ng now to the drawing in more detail, a television receiverincludesl an antenna 8, which receives composite television signals andcouples the received signals to a tuner-second detector 10. Thetuner-second detector 10 would normally include, as is conventional, aradio frequency amplifier, a converter for converting the radiofrequency signals to intermediate frequency signals, an intermediatefrequency amplifier, a detector for separating the video signals fromthe intermediate frequency signal, and a video amplifier. 'l'lheamplified video signal so developed is 4derived from the output lead 12and applied to the control grid (not shown) of a television kinescope14. The video signalsy are also applied to a sync separator circuit 16which is connected with the tuner-second detector i0. The sync separatorcircuit 16 supplies vertical synchronizing pulses to a verticaldeflection signal generator 18, which is connected with the syncseparator circuit 16. The vertical `deflection signal generator 18 is,in turn, connected to a vertical deflection output circuit 20. Thevertical deflection output circuit 20 includes a pair of outputterminals Y-Y, which are connected to the terminals of a verticaldeflection winding 22 of the kinescope 14.

Horizontal synchronizing pulses derived from the sync separator 16 areapplied to a phase detector 24, which is connected with the syncseparator 16. The phase of the horizontal synchronizing pulses iscompared with the v phase of a sawtoot'h current waveform 26, which isdeveloped across a small resistor 28, which is connected in series withthe horizontal deflection winding 29.

The resistor 28 may have a resistance of 0.5 ohm, for example, so thatthe voltage developed across it will have a peak-to-peak value of 1.2volts. Thus, the effect of the resistor 28 on deflection linearity isnegligible, particularly if the deflection winding 29 is not of very lowimpedance. In the present example and for a circuit actually tested andoperated, the deflection winding 29 had an inductance of one millihenrywhile using a resistor 28 having resistance of 0.5 ohm. The deflectionwinding 29 would, in this case, reflect a 62 microhenry inductance tothe output circuit of the output transistor.

.The error voltage developed in the phase detector 24, as a result ofthe phase comparison between the horizontal synchronizing pulses and thesawtooth wave 26, is applied to a horizontal oscillator 30, which isconnectedwith the phase detector 24. The horizontal oscillator V30 isoperative to generate positive pulses 32 in response to this appliederror voltage. The output ter-u minals of the horizontal oscillator 30are connected to the emitter 36 and the base 40 of a driver transistor.`

34.y In this manner, the horizontal oscillator pulses 32 are, analisti`between the, emitter 36, and the base, 4Q of the driver transistor 34.The transistor 34, which 1n the present example, and by way ofillustration only, may be considered to be of the P-N-P junctionY type,1ncludes, in addition to the` emitter 36 and the base 40,` acollectorelectrode 38. The collector 38 of the driver transistor 34 is connecteddirectly to the chassis, of` the television receiver which is at a pointof reference potenf` tialor ground.

The output circuit for` the driver transistor 34 includes atransformer42 having a` primary winding 43 and a secondary winding 44. rl`heemitter 3,6 of the,y driver transistor 34 is connected with theO primarywinding 43;

and a capacitor 45 is connected in parallel with the.

primary` winding 43 to, form a tuned primary circuit. I o provideforward bias for the driver transistorl 3,4, abattery 46 is provided,the negative terminal of which is` connected to chassis ground and; thepositive terminal of which is connected through the primary winding` 43Utothe emitter 36. The battery 4,61may` have inA a, typicalu example, avalue of 13 volts.

The driver transistor 34 is, as described, connected as`acornmonfemitter grounded-collector amplifier. That is, to say, thepulses 32, which are derivedY from, theY horizontal oscillator 30, areapplied to the inputA circuit, that is between the emitter 36 and base40 of the transistor 34, while output signals are derived from betweenthe collector 38 and emitter 36. Accordingly, the emit.-

ter 36 is common to the input and outputI circuits event though thecollector 38 is connectedA directly to ground. In` this manner, maximumpower gain is obtained and the collector 38 of they transistor 34 may bemounted directly on the chassis without electrical insulation'.` Thus, adirect low thermal resistance path between the transistor and thechassis is realized and maximum heat' transfer is provided. The presenceof the driver transistor 34 in the circuit is preferred to achievehigher response time.

Positive pulses 48, which are developed across the;

output circuit of the driver transistor 34 during the re.

trace portion of the deflection cycle as the primary.l

winding 43 goes through a period of oscillation andcur-v rent flowreverses in the transistor 34, are applied through the stepdowntransformer 42 between the emitter- S2 and the base 56 of an outputtransistor 50, such that the base 56 is positive. The pulses 48 are inthe form of one-half of a sine Wave cycle. By transformer coupling thedriver stage to the output stage, a direct current axis about 10 to 15percent above the signal level`v during the scan portion of the cycle isachieved. Thus, a forward bias equal to approximately one-eighthA thepeak-to-peak driving amplitude is supplied to thebase 56` of thetransistor 50. This eliminates the need for` an additional bias supplysource and protects theoutputftransistor in c ase of; driver failures.

T he output transistor 50, which may be considered= to beof the` P-N-Pjunction type, includes, in. addition to theemitter 52 and the base 56,a collector 54. The collector-.54 of the output transistor isconnectedphysicallyand electrically with the chassis, which is at groundpotential, thus` providing maximum heat transfer` as inthe case of thedriver transistor 34. The output-circuit for the output transistor 50includesa transformer 582` having a primary winding 59 and a secondaryWinding 60. This transformer may have a 1 to.4V stepup` turns ratio in atypical example. The emitter 52` is connected with one` terminal oftheprimary: windingV 59. A circuit; 62W3hich'I is tuned; to an odd`harmonic of the ybackt pulse frequency, and in the presentV example willbeassumedto'be tuned tothe third harmonicfrequency, is-connectedr with`the emitterl 52; anda capacitor; 64` isv connectedfrom theotherterminal 1 off the third harmonic circuit` 62 to theA other-- terminalQfthe primary winding battery 6,5Y is provided,A thel negative terminal`of which..

is connected to the chassis ground and the positive terminal of which isconnected through the primary winding 59 to the emitter 52. This batterymay also have a value of 13 volts in the present example.

The high voltage circuit for the kinescope 14 includes a high voltagetransformer 66 which includes a primary winding 67 andv a secondarywinding ,6 8.. The. turns ratio of the high voltage transformer 66 may,for ex ample, be l toy 1,10. One terminal of the secondary windingv 68is grounded, while the other terminal is. connected through a dioderectiier 70 to the ultor connection 72 of the kinescope 14. A capacitor74. is-connected from the junction ofthe diode rectiiier 70 and theultor connection 72 to chassis ground. The circuit is completed, andringing in the deflection circuit is prevented, in accordance with theinvention, by connecting a unilateral conducting device, such as a diode76', in series between the primary winding 59 of` the output transformer58 and the primary winding 67 of the high voltage transformer 66.

In operation, a television signal, which is received by the antenna 8,is amplified and demodulated by the televisionY tuner and seconddetector 10, which would, asnoted above, normally include a radiofrequency amplifier, a` converter, an intermediate frequency amplifier;a detector and a video amplifier. The video signal' appearing at theoutput lead 12 is then applied to the control grid (not shown) of thekinescope 14. Video signals are also applied to the sync separatorcircuit 16, which supplies vertical synchronizing signals to the ver-Vtical deection signal generator 18 and horizontal synchronizing pulsesto the phase detectorV 24.` Output pulses generated by the verticaldeflection generator` 18-` are supplied to the vertical deection outputcircuit 20* which, in turn, supplies a suitable sawtooth of current offield frequency through the vertical deilection windL l ing 22, which isconnected across the output terminals` Y-Y of the vertical deectionoutput circuit 20. As` was explained hereinbefore, a signal 26,corresponding to the horizontal deiiection circuit sawtooth waveform-,is developed across the small resistor 28 in the horizontal outputcircuit and is applied to the phaseA detector 24. The phase of thesignal 26 is compared by the phase detector 24 with the phase of thehorizontal syn-l chronizing pulses, which are applied to the phasedetector 24 from the sync separator circuit 16. In this way an errorvoltage is developed which is dependent onl theV difference in phasebetween the horizontal' sync pulses and the waveform 26 developed acrossthe resistor 28. Thiserror voltage is applied to the horizontaloscillator 30 and is used to control its frequency.

Horizontal output pulses 32, at a frequency deter,- mined by the errorvoltage which is applied to the horizontal oscillator 30, are appliedbetween the b ase 40 and emitter 36 of` the horizontal' drivertransistor 34.y These pulses are of a positive polarity.y The intervalbetween pulses from the horizontal oscillator 30 corresponds to the scanor trace portion of the deflection cycle. During the interval betweenthese pulses the driver transistor 34 is biased for iorwardvconductionand is at saturation. Maximum current thus flows in thecollector-emitter circuit in the direction of the emitter arrow andcurrent ow through the primary winding 43 increases in a linear manner.The application of a positive pulse 32 between the emitter and baseelectrodes of the driver transistor 34V cuts off the drivertransistor34' and reverses the direction ofcurrent ow in the collectoremittercircuit of the driver transistor 34. The driver transistor 34 thereforeacts like a switch and has a small; collector-emitter resistance whilesaturated and` a very large collector-emitter resistance when cut 01T.The emitter-collector` load circuitoi thetransistor, 34V is` opened,

assaut upon application of a positive pulse 32, discharging the energystored in the primary winding 43 through the capacitor 45. This portionof the cycle corresponds to the retrace portion of the horizontaldeflection cycle. A relatively large voltage pulse is developed acrossthe primary winding 43 of the transformer 42. This pulse is stepped downin voltage by the transformer 42 to reduce the circuit impedance, andthe positive voltage pulse 48 is applied between the base 56 and emitter52 electrodes of the horizontal output transistor 50, such that thevoltage on the base 56 is positive.

The output transistor 50, which is also operated as a switch, issaturated during the scan or trace portion of the deflection cycle.Maximum current is thus flowing in the collector-emitter circuit andcurrent through the. horizontal yoke winding 29 is increasing in alinear manner. During the scan or trace portion of the cycle, dampedoscillatory voltages appear across the primary winding 67 of the highvoltage transformer 66. Ordinarily these oscillations would be reflectedback tothe deflection circuit causing ringing in the windings of t-hehorizontal deflection yoke as noted above. This condition causes lightand dark lines to appear on the kinescope raster and is undesirable. Inaccordance with this invention, however, the diode 76 is reverse biasedduring theA scan or trace portion of the cycle. Accordingly,l

the diode 76 presents in effect, an open circuit between the primarywinding 59 of the output transformer 58 and the primary winding 67 ofthe high voltage transformer 66. Accordingly, the high voltagetransformer is isolated from the deflection circuit during scan, therebypreventing damped oscillations from appearing in the deflection circuitand minimizing undesirable ringing.

The application of a positive pulse 48 from the driver transistor 34between the base and emitter electrodes of the output transistor 50causes the output transistor to cut off. Current flow through thecollector-emitter circuit of the output transistor 50 thus reverses. Thecollector-emitter Vload circuit of the output transistor 50 is thusopened, and the energy stored in the primary winding 59 of the outputtransformer begins to discharge. The relatively large positive voltagepulse thus developed on the emitter 52 forward biases the isolatingdiode 76. Current thus flows through the diode 76 and the primary theprimary winding 67 of the high voltage transformer 66,. The voltagedeveloped across the secondary winding 68 of the high voltagetransformer is rectified by the high voltage rectier 70. The resultingcharge which is developed yacross the capacitor 74 is then used vto'supply a direct-voltage for the ultor connection 72 on the kinescope 14.Thus, during the retrace portion of the deflection cycle, the diode 76is conductive and the required ultor voltage is supplied to thekinescope 14,'while during the trace portion of the cycle, the diode 76is open circuited and the high voltage circuit is isolated from thedeflection circuit.

The positive flyback pulse developed in the output circuit of Vtheoutput transistor 50 is reduced in amplitude byV the tuned circuit 62.The tuned circuit 62 is tuned approximately to the third harmonic of thellyback pulse frequency. The voltage across the tuned circuit 62 is adamped sine wave of the third harmonic frequency which is initiated bythe front edge of the flyback pulse. This voltage is 180 degreesout-of-phase with the voltage across the capacitor 64 at the center ofthe ilyback pulse.

Accordingly, the voltage across the tuned circuit 62 reduces theamplitude of the peak output voltage of the transistor 50 and preventsbreakdown of the output transistor 50.

Transistorized horizontal deflection and high voltagek power supplycircuits embodying the invention provide a relatively linear sawtoothcurrent through the horizontal deflection winding of a kinescope and, atthe same time, an ultor voltage for the kinescope. This iS accomplished,moreover, with a single output transistor and without undesired ringingin the deflection circuit. In addition, the circuits are arranged formaximum power gain and heat transfer. The invention thus providesimproved performance with circuits which are relatively economical toconstruct.

What is claimed is:

l. In a television receiver, a horizontal deflection and a high voltagepower supply circuit for an electron beam image reproducing devicehaving a horizontal deflection winding, comprising, in combination, atransistor, means for biasing said transistor in the forward direction,means for applying signal energy to said transistor during the retraceportion of the horizontal deflection cycle to reduce current flowthereof, an output transformer including a primary winding connectedwith said transistor and a secondary winding-connected with saiddeflection winding for supplying a deflection current thereto during thetrace portion of the horizontal deflection cycle, a high voltagetransformer including a primary Winding `and a secondary winding, meansincluding a rectifier connecting the secondary 'winding of said highvoltage transformer with said image reproducing device for applying highvoltage thereto, and means including a unilateral conducting deviceconnected in series between the primary winding of said outputtransformer and the primary winding of said high voltage transformer andpoled to isolate said high voltage power supply circuit from saiddeflection circuit during the trace portion of the horizontal deflectioncycle.

2. In a television receiver, a horizontal deflection and a high voltagepower supply circuit for an image reproducing device having a horizontaldeflection winding comprising, in combination, a transistor switchconnected for common emitter grounded collector operation and includingbase, emitter, and collector electrodes, said collector electrode beingphysically and electrically connected directly to chassis ground forsaid receiver, input circuit means connected for applying signal energybetween said base and emitter electrodes during the retrace portion ofthe horizontal deflection cycle to reduce current flow of saidtransistor, an output transformer including a primary and a secondarywinding, means providing a source of biasing potential, means connectingsaid primary `winding and said source of biasing potential between saidemitter electrode and chassis ground, said source of biasing potentialproviding forward bias for said transistor and maximum conductionthereof during the trace portion of the deflection cycle, meansconnecting said secondary winding with said deflection winding forsupplying a deflection current thereto during the trace portion of thehorizontal deflection cycle, a high voltage transformer including aprimary and a secondary winding, means including a rectifier connectingthe secondary winding of said high voltage transformer with said imagereproducing device for applying a high voltage thereto, and meansconnecting the primarywinding of said output transformer and the primarywinding of said high voltage transformer in series to develop said highvoltage during the retrace portion of the horizontal deflection cycle.

3. In a television receiver, a horizontal deflection and high voltagepower supply circuit for an image reproducing device having a horizontaldeflection winding, comprising, in combination, a transistor, means forbiasing said transistor in the forward direction to provide maximumconduction thereof during the trace portion of the horizontal deflectioncycle, means for applying signal -energy to said transistor during theretrace portion of the horizontal deflection cycle of a polarityl toreduce current flow thereof, an output transformer including a primarywinding connected with said transistor and a secondary winding connectedwith said deflection winding y for supplying a sawtooth deflectioncurrent thereto during the trace portion of the horizontal deflectioncycle, av

ing the secondary winding of said high voltage transformer with saidimage reproducing device, a diode conne'cted in series between theprimary winding of said output 'transformerand the primary winding ofsaid high voltage transformer, said diode being reverse biasedduring thetrace portion of the horizontal deection cycle to isolatey said highvoltage power supply circuit from said deflection circuit and forwardbiased during Vthe retrace portion of the deflection cycle to provide avoltage across said 'high voltage transformer which is rectified by saidrectifier and applied to said image reproducing device.

4. In a television receiver, a horizontal deliection and a high voltagepower supply circuit for a kinescop'e having ahorizontal deectionwinding, comprising, in combination, a transistor including base,emitter, and collector electrodes, means for applying forward bias tothe emitter of said transistor-to provide current saturation of saidtransistor during the trace `portion of the horizontal deilection cycle,means `for applying signal energy between the base and emitterelectrodes of said transistor during the retrace portion of thehorizontal deection cycle to rapidly reduce current flow thereoan outputtransformer including a primary winding connected between kthe collectorand emitter electrodes of said transistor and .a secondary windingconnected with said deflection winding for supplying' a sawtoothdeflection current 4thereto during the trace portion of the horizontaldeflection cycle,l

in seriesto develop said yhigh voltage during the vretrace portion ofthe horizontaldeflection cycle to electrically isolate said high voltagetransformer from said output transformer during the trace portion of thehorizontal deection cycle.

V7. .Ina `television receiver, a horizontal deflection and ahighvoltagepower supply circuit ,for an image reproducing device having rahorizontal deflection winding comprising, in' combination, a driverytransistor including base, `emittenand collector electrodes, saidcollector electrade being-connected directly to chassisfground for saidreceiver 4for effective -ielectrical and heat conductivity f thereto,afhorizontaloscillator.stagefor-generating pulses,

a high voltage transformer including a-primary winding `and asecondary'winding, means including a rectifier connecting :saidsecondary winding with said `lsinescope for applying a high voltagethereto, and meansconnecting :the

the `trace portion of the deflection cycle to isolate said high voltage.power supply circuit from said deflection circuit and in theforwarddirection during the retrace .por-

tion of the deection cycle to :provide current iiowfrorn said transistor'to the primarypwinding of said ,output transformer. s

5. In la television receiver a deflection and a high voltage powersupply circuit for an image reproducing device having a deflectionwinding, comprising, in combination, a transistor, means 4forbiasingsaid transistor in the forward direction, meansffor applying signalenergy'to said transistor to reduce current iow thereof,1an outputtransformer including aprimarywinding connected with fsaid transistoranda secondary winding connected with said deflection Winding forsupplying a deflection current thereto during the traceportion of thedeliection cycle, avhigh voltage transformer including a primarywindingand Va secondary winding, `means connecting said secondarywinding with said imagegreproducing device forapplying a high voltagethereto, and means including a unilateral conducting device connectingtheprimarywinding of said output transformer and the primary windingofsaid high voltage transformer in series. Y

6. `In a television receiver having a chassis `as aicircuit groundmeans, a horizontaldeflection and aihigh voltage power supply circuitfor a `kinescope havingva horizontal deliection winding comprising, incombination,-a transistorincluding base, emitter, andcollector-electrodes,fsaid collector `electrode being physically andelectrically .connected directly to said chassis, input lcircuitmeansconnected 4forapplying `signal energy between said -baseand emitterelectrodes duringithe retrace portion of thehorizontaldeflectioncycle-and of polarity to reduce current `liow` of said transistor,anout-put transformevincludinga primaryfand a secondary winding, means`providing a source of biasing potential for said transistor, meansconnecting said primary winding and saidnsourceof biasing potentialbetween said `ernitter lelectrode and chassis ground,` said source ofbiasing potential'providingforward bias for the emitter electrode of-said transistor, means connecting said secondary Winding with :saiddeiection k primary :windingof said'output transformer and ythepribiaslvoltage to said output means connecting said horizontal oscillator:stage with said driver 4transistor Vfor applying said .pulses betweensaid baseand'emitter electrodes during the yretrace portion ,ofk

the Vhorizontal deflectioncycle, a -first transformerincluding;aprimar;yand a secondary -winding,rneans connecting said'primary winding between said emitter and lcollector electrodes, meansconnected Tfor applyingia forwardbias voltagefto -said transistor, anoutput :transistor :including basepemitter, and 'collector electrodes,`the collectorelectrodelofsaid output transistorheing connected`directly to chassis yground -for effective electrical andheat:conduction thereto, kfmeans connecting said secondarywindingwiththe :base vand emitter electrodes of said output transistor forAapplyingspulses thereto during'the retrace portion ofthehorizontalzdeection icycle,an outputtransforiner in-V cluding-aprimary `and a secondary winding, meansconnecting ysaid Vprimary windingbetween `the Y,emitter and collector electrodes of .said s outputtransistor, means ,conf nectingthe secondary winding ofi-said outputtransformer with said deflection Iwinding yfor applying a sawtoothdeection current thereto `during the trace portion of the de-` iiectioncycle, means connected for applying a forward transistor, y a @highvoltage transformeriincluding a primary and'a secondary -windingof` saidhigh voltage transformerwith sald lmage `reproducing device forapplyingahigh voltage theretepand meansincluding a` diodeconnectingtheprimary winding i of saidtoutput transformerand thefprimary,Windingpf saidliigh voltage vtransformer in series itoidevelop saidhigh voltage atthe secondary-duringtheiretraceportion of theVdeflectioncycle and `to `isolate said high `voltage transformer `from-said output "transformercdnring the trace portion ofthedeliectioncycle.

8. In a television receiver including a kinescopefhaving a'deflectionWinding, a horizontal deflection andra high voltage 4power supplycircuit comprising, inl combination,

atransistor connected and biased-to be operative at-saturation'andinallow resistance conditionduringithetrace` portion ofthe horizontaldeflection cycle, means-for applying-input pulsesfto-said transistorduringthe'retrace portionof theinput` cycle torender saidtransistormonconductive and in `a relatively high resistance.'condition, `an output transformer'inclnding aprimarywindingcom nectedwith said transistor `and a'secondary winding connected with saiddeflection winding for supplying a'deflection current' thereto duringthetrace portion ofthedeflec- -tioncycle, a high voltagepower supplytransformer'invcluding a primary winding an'd a secondary winding meansconnecting said `secondary winding with .said kine- .scope forfapplyinghigh operating voltages thereto, and a diode connectedbetween theprimary winding of said output transformer and `the .primary winding ofsaid high voltage power supply transformer and defining a series circuittherewith, said diode being poled in said circuit to eiect an opencircuit between said primary windings during the trace portion of thedeflection cycle and a short circuit between said primary windingsduring the retrace portion of the dellection cycle.

9. In a television receiver including a kinescope having a deflectionwinding the combination comprising, a transistor including base,emitter, and collector electrodes, an output transformer including aprimary winding and a secondary winding, means connecting said primarywinding between said emitter and collector electrodes, means providingforward bias for said transistor to provide maximum conduction thereofduring the trace portion of the horizontal deflection cycle, meansconnecting said collector directly to chassis ground for effectiveelectrical and heat conduction thereto, an input transformer including asecondary winding connected between said base and emitter electrodes forapplying signal energy thereto during the retrace portion of saiddeflection cycle of a polarity and amplitude render said transistornonconductive, means connecting the secondary winding of said outputtransformer with said deflection winding for supplying a deflectioncurrent thereto, a high voltage transformer including a primary and asecondary winding, means connecting the secondary winding of said highvoltage transformer with said kinescope, and unilateral conducting meansconnecting said primary windings in series and poled to isolate saidoutput and high voltage transformers during the trace portion of thedetlection cycle.

10. In a television receiver, a horizontal deflection and a high voltagepower supply circuit for an image reproducing device having a horizontaldeflection winding comprising, in combination, a transistorbidirectional switch connected for common emitter-grounded collectoroperation and including base, emitter, and collector electrodes,

said collector electrode being physically and electrically connected tochassis ground for said receiver, input circuit means connected forapplying signal energy between said base and emitter electrodes of apolarity to reduce current iloW of said transistor during the retraceportion of the deflection cycle, a voltage supply source poled to applya forward bias voltage to said transistor to provide maximum conductionthereof during the trace portion of the deflection cycle, output circuitmeans including said horizontal deflection winding connected with saidtransistor for applying a deflection current to said deflection windingwhich increases in a substantially linear manner to provide deflectionof an electron beam of said image reproducing device during the traceportion of the horizontal deflection cycle, a high voltage transformerincluding a primary and a secondary winding, means directcurrentconductively connecting said primary winding and said voltage sourcebetween said emitter electrode and chassis ground to apply said forwardbias voltage to said transistor and defining with at least a portion ofsaid output circuit a series circuit for developing a high voltageduring the retrace portion of the deflection cycle, and means includinga high voltage rectifier connecting said secondary winding with saidimage reproducing device for applying said high voltage thereto.

References Cited in the file of this patent UNITED STATES PATENTS2,784,262 Crow Mar. 5, 1957 2,794,076 Shea May 28, 1957 2,801,298 Mitalluly 30, 1957 OTHER REFERENCES

